A database is a collection of logically related data arranged in a predetermined format, such as in tables that contain rows and columns. To access the content of a table in the database, queries according to a standard database query language (such as the Structured Query Language or SQL) are submitted to the database. A query can be issued to insert new entries into a table of a database (such as to insert a row into the table), modify the content of the table, or to delete entries from the table. Examples of SQL statements include INSERT, SELECT, UPDATE, and DELETE.
Relational tables in some databases can be quite large, with some tables having millions of rows of data. Accessing such large tables when processing queries can be time-consuming and computational-intensive. Although traditional SQL statements provide for good flexibility in accessing data contained in tables, such SQL statements typically do not provide a convenient way of recognizing patterns that may be present in tables.